The present invention relates to a novel immediate-release morphine sulfate formulation for oral administration.
In addition, the present invention applies to the process for manufacturing this formulation and to the pharmaceutical preparations comprising it.
In the present application, xe2x80x9cmorphine sulfatexe2x80x9d is understood to mean the sulfate salt, optionally hydrated, of (5xcex1,6xcex1)-7,8-didehydro-4,5-epoxy-17-methyl-morphinan-3,6-diol.
In the present application, xe2x80x9cimmediate-releasexe2x80x9d is understood to mean that an active principle, in this case morphine sulfate, is made available in the body at a rate such that the plasma concentration of active principle is therapeutically effective and below the toxic concentration for a period of time of less than approximately 4 hours.
The oral administration of morphine is regarded as the treatment of choice for chronic pain.
The document EP 655,240 discloses a prolonged-release tablet comprising an immediate-release core including acetaminophen and morphine which causes the release of more than 75% of the acetaminophen in 45 minutes when it is placed in 900 ml of a 0.1N hydrochloric acid solution.
The document U.S. Pat. No. 5,445,829 discloses a formulation comprising a mixture of immediate-release particles and of delayed-release particles. The immediate-release particles are obtained by spraying a solution of binding agent over a mixture of active principle and of inert grains. The immediate-release particles comprise a binder which represents between 4 and 8% of the morphine sulfate/binder mixture.
The document U.S. Pat. No. 5,026,560 discloses granules obtained by powder spraying. These granules are composed of a neutral core coated with a mixture of active principle and of weakly substituted hydroxypropylcellulose. The binder used is an aqueous hydroxypropylcellulose solution.
The document WO 95/31972 discloses an immediate-release multiparticulate oral formulation comprising microgranules composed of a neutral core coated with a mixture of active principle, in particular morphine sulfate, and of a diluent, such as lactose hydrate, exhibiting a bulk density of between 0.4 and 0.9 g/ml. The document WO 95/31972 teaches that the binding of the morphine sulfate to neutral cores requires the addition of a diluent in order to obtain good results.
The document WO 96/00066 discloses controlled-release morphine tablets for oral administration. These tablets are obtained by successively compressing two compositions: a first so-called xe2x80x9ctherapeuticxe2x80x9d composition obtained by wet granulation of a mixture comprising morphine sulfate, one or more poly(alkylene oxide)s and polyvinylpyrrolidone and a second composition obtained by wet granulation of a mixture comprising a poly(alkylene oxide), sodium chloride and hydroxypropylmethylcellulose. The tablet thus obtained comprises an active principle composition coated with a porous semi-permeable membrane which controls the rate of release of said active principle.